Design of InGaP//GaAs thin-film tandem solar cell architecture for space applications

Abstract The power conversion efficiency of the single junction solar cell is approaching the theoretical limits, which leads to the development of tandem cells. The Si-based space photovoltaics (PVs) need expensive encapsulation to protect the cell from extreme radiation. Considering the circumstances, the study presents a design and simulation of InGaP//GaAs thin-film tandem solar cell architectures tailored for space applications due to the high-temperature stability, radiation resistance, longer minority carrier lifetime, and higher electron mobilities. The novelty of the work includes consideration of the heavily doped absorber material for a back surface field (BSF) and investigation of a wide temeperature variation under the space solar spectrum. The optimized InGaP/BSF top and GaAs/BSF bottom cells are 17.95% and 24.67% efficient, respectively. Tandem two-terminal and four-terminal (4 T) configurations achieved efficiencies of 30.47% and 33.17%, respectively, under AM1.5 G, which are close to the fabricated cells. The work also explains the impact of space radiation on PVs with the reported solutions to support the work. With a rise in temperature from 125 K to 400 K, the optimized 4 T tandem cell power generation decreases within an acceptable limit, showing the applicability in the space temperature range. As the proposed cell is a thin-film tandem cell with minimal material utilization and resistance to high-energy radiations, it sets a new avenue in PVs for space applications.